Dial and cylinder knitting machine having self-frictioning needles

ABSTRACT

A circular dial and cylinder type knitting machine having narrow needle grooves and a thin guage straight unbent needle in each groove pressed against one groove side by a spring carried by the needle in a slot in its side, the spring engaging the opposite groove side, in all positions of the needle; a needle as described.

United States Patent 091 Kohorn [54] DIAL AND CYLINDER KNITTING MACHINE HAVING SELF- FRICTIONING NEEDLES [76] Inventor: Alfred O. Kohorn, 862 Wycoff Avenue, Brooklyn, NY. 11227 [22] Filed: June 23, 1971 [2]] Appl. No.: 156,056

Related US. Application Data [63] Continuation-in-part of Ser. No. 854,901, Sept. 3,

1969, abandoned.

[52] US. Cl. ..66/l9, 66/121, 66/124 [51] Int. Cl. ..D04b 9/06, D04b 35/04 [58] Field of Search ..66/123,l24, 121,19

[56] References Cited UNITED STATES PATENTS 433,747 8/1890 Scott ..66/124 1,483,844 2/1924 Drumheller ..66/l9 2,004,617 6/1935 Roy ..'....66/l24 [1 1 [451 Jan. 23, 1973 2,024,911 12/1935 Crawford ..66/124 2,592,787 4/1952 3,220,221 11/1965 3,576,115 4/1971 468,513 2/1892 2,677,257 5/1954 Jarvis ..66/124X FOREIGN PATENTS OR APPLICATIONS Great Britain .66/ 124 Switzerland ..66/ l 21 Primary Examiner-Robert R. Mackey Attorney-Irvin A. Lavine [57] ABSTRACT A circular dial and cylinder type knitting machine having narrow needle grooves and a thin guage straight unbent needle in each groove pressed against one groove side by a spring carried by the needle in a slot in its side, the spring engaging the opposite groove side, in all positions of the needle; a needle as described.

5 Claims, 6 Drawing Figures Y FIG. 5

PATENTEDm 23 1915 FIG. 6 1

mvmmon ALFRED O. KOHORN DIAL AND CYLINDER KNITTING MACHINE HAVING SELF-FRICTIONING NEEDLES CROSS REFERENCE TO RELATED APPLICATION This application is a continuation of copending application Ser. No. 854,90l,filed Sept. 3, 1969, now abandoned.

BACKGROUND OF THE INVENTION The present invention pertains to a high-speed circular knitting machine, preferably of the dial and cylinder type, having thin gauge needles provided with springs.

Where high production quantities of knitted goods are desired, circular knitting machines are used. The dial and cylinder type circular knitting machine is generally acknowledged to have the highest productive capacity. Such machines typically operate at approximately 2l R.P.M., having advanced to this speed from the prior standard speed of approximately l2 R.P.M. Concommittant with the increase in speed, and therefore productive capacity, of these machines, there has been a reduction in the thickness of the needles used in them, the generally accepted standard needles at the present time having a thickness of approximately 0.018 inches to 0.023 inches. This contrasts with the thicker needles formerly used, which were approximately 0.035 to 0.045 inches in thickness. It will be understood that the reduction in needle thickness has reduced the mass of the needles, and has thereby reduced stresses arising from movement of this mass, although it is to be appreciated that overall momentum and stresses resulting therefrom have not necessarily been reduced, because while the needle thickness, and therefore weight, has been reduced, the needles have been moved at higher speeds, which has therefore offset the reduction in needle thickness and weight.

Needles are, in the substantially universal practice, bent transversely to the longitudinal axis of the needle so that the needle has a resilient, frictional engagement with the walls of the needle groove or trick in which it operates. This bending of the needle is done in order to provide a brake for the needle, thereby preventing it from working loosely in its slot. The bending of the needles is not precise, and there is no assurance that all the needles of a particular machine will be bent the same amount. When it is recognized that in some standard machines, there may be approximately 3,500 needles per machine, it will be understood that variation in the amount of bending of the needles, and there-fore the frictional engagement and braking effect of these needles, will vary to an appreciable extent.

More particularly, it is the common practice in the present time in order to facilitate bending, to provide the needles of dial and cylinder machines with a portion of reduced thickness, somewhere rearwardly of the hook, at a place which will always be in the groove of the knitting machine in whatever position the needle may take in that groove. The reduced thicknessportion is typically provided by milling, and is known as the flex band. The resulting bent needle has two portions which are at small angles to each other, and consequently the heads or hook ends of the needles do not extend straight out of the needle grooves, but instead many of the needle heads or hook ends will have their median planes at an angle to the median plane of the needle groove in which the needle is located. The needie engages the walls of the needle grooves at two or three spaced points. This is a matter which has been found to be of considerable importance, since the heads of the dial needles must pass between the heads of the cylinder needles, and vice versa. In the engineering of present knitting machines, a minimum clearance between the heads of the dial needles and the heads of the cylinder needles is provided: the inclination or slanting of the needle heads, due to the above noted flexing, causes the dial needle heads to rub against the cylinder needle heads. In addition, because of the noted spaced-point needle-to-groove wall contact,

there results considerable vibration of the needle heads during the high speed knitting operations because the forward portions of the needles are substantially free of contact with the needle groove walls forwardly of the flex band. The slanting and the vibration have been found to be the cause of dial and cylinder needles at times striking each other, so as to result in breakage of needles and damage of the cloth being knit: breakage of needles of the bent flex band type has averaged approximately 15 needles broken per normal week of operation.

It has been known that in the circular high speed knitting machines, the bent needles have, after a period of time, lost resiliency, due to the effect of the heat generated in the machine, the needles thereby in essence performing as if they were not bent uniformly, and were not braked uniformly by this bent configuration. The non-uniformity of needle bending has been discovered to be a primary cause of the upper limit of circular knitting machine operating speed to the above mentioned 20 21 R.P.M. Further, because of the above mentioned heating, some needles lose more of their bend and resiliency than others, which results in some needles running comparatively looser and others comparatively tighter, in their grooves of the dial and cylinder. Those needles which run looser make a tighter stitch, which shows up as a defect in the knitted fabric as a vertical tight line, while those needles which are tighter in their grooves make a looser stitch, and this shows up as larger stitches in the knitted fabric. In either case, the fabric is defective and cannot be sold as a first class product; unfortunately, the defects such as the needle lines above mentioned, are hardly apparent in a knitted fabric until it is dyed, so that an unduly large amount of material is, as a consequence, sold as second or third class material, with resultant loss of income.

As long ago as I890, it was suggested that a knitting machine needle could be provided with a separate spring US. (Pat. No. 433,747), but despite this disclosure, no known knitting machine needles are manufactured today, throughout the world, having a spring; instead, even with the higher speeds of circular knitting machines above mentioned, the same practice of bending the needles transverse to the needle longitudinal axis, which existed prior to I890, is still being used. In the noted needle, separate springs were associated with the needles without any other fastening than the mere fitting of the parts together. Hence, these springs would be prone to becoming separated from the needles, especially during handling prior to insertion in the knitting machine.

In knitting machines which operate at relatively low speeds, which are characterized by having flat beds and which are often designated as Links-Links" machines, jacks have been provided which are used to drive needles having two heads, and which are moved from one bed of the machine to the other. Such jacks, which are of considerably greater thickness than the thickness (0.019 inches) of the above mentioned needles, have been provided with springs attached to them, these springs being used to cause the jacks to fall into the needles head; these machines do not have the problems of vibration and a limiting of speed caused thereby which is found in the high speed circular knitting machines. These relatively thick jacks have been provided with grooves or slots in their sides, with a spring being fastened to the jack and being generally positioned at the groove or slot. Typically, a leaf spring was provided having one end secured or anchored to the needle shank at its reduced portion at the groove or slot. See U.S. Pat. Nos. 1,940,520 and Pat. 2,219,600 for example.

Also known in the prior art are several types of transfer needles used in circular knitting machines. In one type, a leaf spring is provided at one or both sides of the needle, and these springs primarily function as stitch transferers, being placed on the needle sufficiently close to the hook that during the transfer operation, the spring or springs is not in the needle groove. This occurs when the needle is in its most projected position, so that the transfer spring is out of the needle groove when the needle is in its least supported position. Typically, the machine is slowed down during the transfer operation.

In another type of transfer needle, the needle has an increased thickness over the normal needle of at least two times, and requires modification of the dial in which it is used in order to accommodate its additional thickness. In addition, this needle, to accommodate the cylinder needle with which it cooperates, is provided with a trough, thereby resulting in a needle with an arcuate shape in the longitudinal direction rearwardly of the hook, which causes the needle hook to be prone to vibration; such vibrations would not be overcome by a presser spring fastened to the side of the needle at the tail thereof.

SUMMARY OF THE INVENTION The present invention provides a high speed circular knitting machine, preferably of the dial and cylinder type, in which straight, unbent, integral needles are provided in the needle grooves, which needles are relatively thin and have slots or grooves milled or otherwise fashioned in the sides of the needle shanks. A leaf spring is provided at the groove or slot in the needle shank, having one end thereof firmly secured to the needle, as by welding or riveting. The spring may also be of wire. The spring is positioned on the needle sufficiently far from the hook so that it is always in the needle groove of the machine, and always presses the needle in planar surface-to-surface engagement with the side of the needle groove, This engagement provides substantial support for the needle during machine operation, resulting in reduced needle vibration and breakage, and resulting in increased machine speed of about four revolutions per minute, giving an increase in production of about percent.

Among the objects of the present invention is to provide a circular knitting machine capable of a substantially higher speed, and therefore higher productivity, than known knitting machines. Another object of the present invention is to provide a knitting machine with improved needles which have substantially uniform braking action with the needle grooves, over a longer period of time than presently known constructions. A further object of the present invention is to provide a knitting machine and needle combination in which the production of high quality knitted fabrics will be increased over that obtainable with prior known constructions. A still further object is to provide a circular knitting machine having reduced needle vibration and breakage even with thin needles. Other objects and many of the attendant advances of the present invention will be readily understood from the following Specification and Claims.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an elevational view, with parts in sections, showing a part of a knitting machine and needle combination in accordance with the present invention.

FIG. 2 is an elevational view of a needle forming part of the present invention combination.

FIG. 3 is a plan view of the needle of FIG. 2.

FIG. 4 is a plan view showing the needle of FIG. 3 in a needle groove.

FIG. 5 is a partial view of another embodiment.

FIG. 6 is a cross-sectional view taken on line 6-6 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawing, wherein like or corresponding reference numerals are used to designate like or corresponding parts throughout the several views, there is shown in FIG. 1 portions of a circular knitting machine generally designated 10, and comprising a dial 1] and cylinder 12. It will be understood that these parts are relatively conventional, and comprise a plurality of needle grooves or tricks for receiving needles I5. While it is typical for the dial needles to vary in size and/or shape from the cylinder needles, the dial needles I5 and the cylinder needles 15 are here shown, for purposes of simplicity, to be of substantially the same size and shape.

In a typical, high speed circular knitting machine, the rotational speed is approximately 20 2l R.P.M., and it is such a machine which is herein illustrated. These machines have needle grooves of approximately 0.025 to 0.027 inches, and the needles have a thickness of approximately ().020 inches, usually ranging in thickness between 0.018 inches and 0.023 inches. It will be seen, therefore, that a clearance of only approximately 0.006 inches is provided for these needles. It will also be seen that these needles are extremely thin, having been reduced in thickness to the minimum amount believed feasible at the present time.

Referring now to FIG. 2, the straight, unbent needle 15 shown therein has at its forward end a hook 16 with latch 17, cut out portions 18 and 19 at the bottom thereof, and a pair of spaced, upstanding butts 21 and 22. In FIG. 3, it will be seen that the shank of the needle 15, which for the most of its length has a thickness of approximately 0.020 inches, has been reduced, so as to provide a groove or slot 25 in the side thereof. The groove or slot has a depth of approximately 0.007 inches, so that the needle shank at the groove or slot 25 has a thickness of only approximately 0.012 inches. In the groove or slot 25, there is an arched spring 30 having an end 31 securely anchored to the shank of needle 15 by a pair of rivets 32. It will be understood that other means may be utilized for securely anchoring one end of the spring 30 to the shank of theneedle 15 such as, by way of example, welding, cementing, etc. The opposite end 33 of the spring 30 is free, and upon flexing of the arched portion of spring 30 towards the shank of needle 15, the free end 33 of spring 30 will move towards the hook 16, as permitted by the excessive length of the slot 25 relative to the length of the spring 30. The spring 30 is of material, such as spring steel, which will retain its resiliency over a long period of time, even when under stress and at the relatively high temperatures which occur in such knitting machines.

In FIG. 4, there is a view ofa portion of a needle bed of the circular knitting machine 10, there being shown in FIG. 4 a pair of upstanding ribs 35, 36, with a needle 15 in the groove between them, the needle 15 being pressed against the side of rib 36 by the resilient action of the spring 30, a portion of which engages the facing side of the rib 35. The sides of the ribs which define the needle grooves are flat, planar surfaces, in parallel relationship, and since the needles are straight and unbent, one side of each needle is thereby pressed into substantial surface-to-surface engagement with a groove side by the spring 30. As is apparent from FIG. 1, the spring 30 is sufficiently far from the needle hook that the spring is in the needle groove in any position of the needle during knitting operation of the knitting machine to provide support for the needle over all of its length, except for that portion extending longitudinally beyond the ribs 35, 36 when the needle is moved forwardly for knitting.

FIGS. 5 and 6 disclose an embodiment in which the needle 15A, shown in partial view, has a groove 25A which is less than the full height of the needle 15A, and an arched spring 30A made from a wire is positioned in the groove 25A. The end of the wire spring 30A is secured to the needle shank, as by rivet 32A, and the groove 25A is slightly larger than spring 30A, to thereby guide it.

In operation, the circular knitting machine rotates at a speed of 23 to 23 R.P.M., which is significantly higher speed than the presently attainable maximum speed of 20 21 R.P.M.; thus productivity is increased about 20 percent. The needles or 15A, not being relied upon to effect a braking action by a bent configuration, and having separate, uniform springs 30 or 30A, will have a substantially uniform braking function as they operate in the needle grooves of the machine 10. The springs 30 or 30A will bear against one side of the needle grooves, and thereby press the needles against the opposite side of the grooves. This pressing and the surface engagement of the needles and groove sides reduce vibration of the needle; and specifically of their hooks, during knitting. Thus the needle hooks operate with little vibration and tend to remain in their theoretical or design paths, thereby substantially reducing the striking of other needles during knitting. This reduces the needle breakage rate from that experienced with machines with bent needles from about 15 needles per week to an experienced breakage of only 17 needles in four months of operation. Also the needles herein provided in the machine 10, and forming a part thereof, are sufficiently strong to operate for extended periods without significant breakage.

There has been provided a circular knitting machine having a substantially higher speed, and therefore, higher productivity, than has previously been attainable. Further, the present invention knitting machine is capable of operating at such high speeds and high productivity for a longer period of time than was possible with heretofore known machines, because of the fact that the braking effect produced by the separate spring elements is substantially uniform throughout the numerous needles of the machine, and because these separate spring elements, attached to each of the needles, are not prone to being separated from the needles, and are further not susceptible, as in the case with braking obtained from bent needles, to loss of resiliency due to heat. As a consequence, the machine of the present invention comprising the needles illustrated herein, is capable of manufacturing first-class, unblemished fabric, due to the fact that the needle movement is established as being relatively uniform, and remains relatively uniform, over a relatively long period. The above superior results have been achieved through the utilization in a circular knitting machine of a separate spring element securely affixed to the needle at a portion of the needle having a reduced thickness, and without significant loss in the strength of the needle. This has been accomplished, also, with relatively thin needles which have been provided in the art in order to achieve the heretofore high speeds of operation, and therefore the heretofore known high rates of productivity.

It will be obvious to those skilled in the art that various changes may be made without departing from the spirit of the invention and therefore the invention is not limited to what is shown in the drawing and described in the Specification but only as indicated in the appended claims.

I claim:

1. In a high speed circular knitting machine operating at a minimum of approximately 20 r.p.m. having a dial and cylinder, each having needle grooves therein, said grooves each being defined by a pair of spaced straight, planar and substantially parallel groove walls,

the improvement comprising latch needles in said grooves each comprising a straight, unbent longitudinally extending member integral throughout the length thereof and having a hook at one end and integral butt means extending transversely to the longitudinal axis for cooperation with cams to effect longitudinal movement of the needle in its groove,

said needles comprising spring means inseparably carried by said member and extending from one side thereof, said spring means being at a place spaced from said head a distance to remain in the needle groove in all positions of said needle in said groove and substantially spaced from the end of the needle opposite the head thereof,

said spring means engaging a said groove wall and urging the other side of said needle into planar sur- 3. The circular knitting machine of claim I, and securing means for said spring means comprising a rivet.

4. The circular knitting machine of claim 1, said spring means being a wire element.

5. The circular knitting machine of claim 1, said needle grooves having a width of about 0.026 inches and said needles from about 0.018 up to about 0.023 inches in thickness. 

1. In a high speed circular knitting machine operating at a minimum of approximately 20 r.p.m. having a dial and cylinder, each having needle grooves therein, said grooves each being defined by a pair of spaced straight, planar and substantially parallel groove walls, the improvement comprising latch needles in said grooves each comprising a straight, unbent longitudinally extending member integral throughout the length thereof and having a hook at one end and integral butt means extending transversely to the longitudinal axis for cooperation with cams to effect longitudinal movement of the needle in its groove, said needles comprising spring means inseparably carried by said member and extending from one side thereof, said spring means being at a place spaced from said head a distance to remain in the needle groove in all positions of said needle in said groove and substantially spaced from the end of the needle opposite the head thereof, said spring means engaging a said groove wall and urging the other side of said needle into planar surface-to-surface engagement with the opposite groove wall, whereby as said machine knits, each said needle will move longitudinally in its groove with substantial planar surface contact between a side of the shank thereof and said groove wall with resulting support of said needle and minimal vibration of said hook, and machine speed and productivity are increased and needle breakage is decreased.
 2. The circular knitting machine of claim 1, said spring means comprising a leaf spring.
 3. The circular knitting machine of claim 1, and securing means for said spring means comprising a rivet.
 4. The circular knitting machine of claim 1, said spring means being a wire element.
 5. The circular knitting machine of claim 1, said needle grooves having a width of about 0.026 inches and said needles from about 0.018 up to about 0.023 inches in thickness. 